Marty:
> Jochen Schulz wrote:
> >
> >Again, I think you are searching in the wrong direction. Your 'hdparm
> >-tT' results clearly showed that the great difference between your
> >servers doesn't lie in hard disk performance (48 to 43 MB/s), but in
> >Memory/CPU performance (278 to 58 MB/s).
>
> That would be a very gross misconfiguration.
Yes, obviously! ;-) I didn't make these numbers up, they are from the
OP's hdparm runs.
> To me it seems far more
> likely that raid caching is simply disabled, possibly in the driver.
I must give in I don't know anything about raids, but I can read the
hdparm manpage. As I quoted in another message, the numbers above
clearly show that the combination of memory and CPU on the one system is
220 MB/s faster than the other one (because that is what -T does).
And again: even if the hard disk was badly misconfigured - if you do the
same query (read-only) several times, the Linux kernel should cache your
reads so that the hard disk isn't even accessed. Provided that the
system has enough memory, of course.
J.
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